Guest blog: Ground roosting Stock Doves and nocturnal bird ringing

For a number of winters I have been surveying and ringing Woodcock on my local New Forest heaths and farm fields. In November 2012, on a particularly wild, wet and windy night on the Forest, I saw what appeared to be a small pale plastic bag on the ground. However, despite the strength of the wind, the bag remained perfectly still. I was intrigued and decided to have a closer look.

To my amazement a head suddenly popped up out of the object and I realised that I was looking at some sort of dove. A tired racing pigeon perhaps, caught out by the rough weather, or injured and forced to resort to cowering on the ground? However, when about five metres from the bird, I was even more amazed to see that the bird was in fact a Stock Dove.

I still thought that it must be unwell or it had been blown out of the tree in which it had been roosting. I debated whether to catch the bird or leave it to recover. If it was injured, perhaps I could take it into care, therefore I opted to catch the dove. Once I had the bird in my hands, it was obvious that there was nothing wrong with it. Furthermore this Stock Dove was an adult with perfect plumage and a high weight. So what was it doing roosting on the ground, when there was suitable dense woodland nearby?

Stock Dove, ringed at night on a New Forest heath (Photo: Graham Giddens)

At that stage in my Hampshire Woodcock-catching career, I had been ringing winter Woodcock for three years, and 2011 was my first year ringing on the Forest. During that time I had encountered a wide variety of other species feeding or roosting on the ground at night: Red-legged Partridge, Golden Plover, Lapwing, Jack Snipe, Snipe, Curlew, Barn Owl, Little Owl, Short-eared Owl, Skylark, Woodlark, Meadow Pipit, Fieldfare, Redwing, Song Thrush and Wheatear had all been encountered, but never a pigeon or a dove.

Thinking that this was a crazy one-off experience, I wrote up my notes and moved on, to try to ring more of the main study species: Woodcock. However, two months later, again on the Forest heaths, I caught two more ground-roosting Stock Doves, both of which were also adults in fine condition, and I saw a few more, which made me stop to think: ”Maybe these doves are deliberately roosting on the ground at night.”

Around the same time I was looking at the Welsh Ringer’s blog ‘Ruffled Feathers’, and noted that they were also occasionally coming across Stock Doves at night. In discussions with fellow Forest Woodcock ringers, Nigel Jones and Manuel Hinge, they too were beginning to see the same species exhibiting the same behaviour.

Therefore, I decided to look at my observations for numbers of Woodcock and other species seen on the nights when Stock Doves were present. On those nights, it transpired that there was a corresponding increase in all migrant species, notably more Woodcock and more winter thrushes. The Woodcock move out onto the heaths at night to feed and then roost, but winter thrushes seem to sometimes settle among the grass and heather for the sole purpose of sleeping – behaviour that appears seriously dangerous, because there are Foxes, Badgers and occasional owls out on those same heaths at night, all looking for an easy meal. At least the thrushes have dark-coloured backs for camouflage, unlike the ghostly pale grey-blue of a Stock Dove!

The arrival of larger numbers of migrants coincided with the expected climatic conditions, for example, arrivals in late autumn as cold weather begins to grip Scandinavia and eastern Europe, and cold snaps in other regions of the UK and Europe during the course of winter, prompting birds to come our way.

Could it be that the Stock Doves, like the Fieldfares and Redwings, were newly arrived migrants and, not knowing the area where they had just arrived, opted to stay on the ground? Maybe the thought of going into unknown woodlands populated by potential threats such as Tawny Owls was more frightening than being in the open?

A Stock Dove in its more typical New Forest woodland habitat (Photo: Marcus Ward)

The results of years of ringing data show us that the likes of Fieldfare and Redwing come to us in autumn from breeding grounds to the north and east. Little is known about the migratory populations of Stock Dove, but the species does breed in southern Scandinavia and eastern Europe, two regions that can suffer from heavy winters, pushing many bird species our way.

Here in Hampshire, on the coast in autumn we often see large movements of Woodpigeons, either coming in from the European Continent or moving along the coast, perhaps having originated from Scandinavia. Among these large migrant flocks one can usually pick out small numbers of Stock Doves moving with the pigeons. At the same time, despite its national Amber Listing, the Stock Dove appears to be thriving as a breeding species in Hampshire. There is also some evidence to suggest that the species is expanding its range in Scandinavia, thus creating more migrants for us to see here in winter.

Large numbers of migrant Woodpigeons can be seen moving along the Hampshire coast in late autumn, usually with a few Stock Doves mixed in (Photo: Russell Wynn)

Despite the two species often being seen feeding and flying together during the day, none of us has ever seen a Woodpigeon roosting on the ground at night. When we encounter Stock Doves roosting on the ground, they are always single birds. On one night I did catch three separate Stock Doves at one site, but each bird was more than 100 m from the other.

I am by no means certain and it would take a summer ringing recovery in Sweden or Lithuania to conclude my theory, but there is good evidence that backs up my idea that the New Forest and other parts of the UK now attract migrant Stock Doves in winter, some of which sometimes choose to roost on the ground at night. The behaviour may be something new, it is not described in any ornithological literature, but then perhaps it has only been uncovered because keen ringers (aka total nutters!) like Nigel, Manuel and me have begun to go out to investigate what is out there in the night.

Many other interesting observations have arisen as a result of the Woodcock ringing. For example, in recent winters I have noticed and ringed my first ground-roosting Blackbirds and Mistle Thrushes, completing the set of all five winter thrushes ringed at night. Although both are locally common resident species, they can also be migrants. Like the Stock Doves, I assume that those thrushes that I have found are also migrants, but why have I only encountered these two species in the most recent winters?

The status of Jack Snipe, which was formerly believed to be a scarce wintering species, may need to be revised. At some sites, this species magically drops in on a regular basis, sometimes in impressive numbers. We have ringed some, along with a few Mallard and Teal, and one of the latter turned up in France later in the same winter.

The best surprise was bumping into a small flock of three Grey Plovers at a Forest site. This place is only 4 km from the coast, but I was not aware that this species used the Forest heaths. I managed to ring one of the plovers, which was a first-winter, a feat that has been repeated three winters in a row at that one site. They may only occur in small numbers, but the Woodcock study has proved that Grey Plovers do regularly come onto the Forest at night.

Through a lot of long nights in the field studying the Woodcock, we have learnt a great deal, but it is amusing that there were also so many unexpected surprises out there, just waiting for us to accidentally discover!